(Greek, horned fern). Ceratop-teridacese. Very succulent tropical ferns, forming also a distinct family. They are the only truly aquatic plants among true ferns and grow floating or rooted under water in the mud or sometimes only occasionally flooded. The leaves are borne in rosettes, the sterile spreading, often floating, the fertile more erect, 2-4-pinnate, with very slender rolled-up pod-like segments: sporangia very large, borne separately along the veins and covered by the revolute margins somewhat as in Pteris. - Species very few. Best grown by planting in pots, slightly submerged. Reproduced by buds which arise from all parts of the leaves New plants must be developed each season. Useful in ponds and aquaria.

Ceratopteris pteridoides. (X 1/3)

Fig. 879. Ceratopteris pteridoides. (X 1/3)

Pteridoides

Hook. Fig-. 879. Sterile leaves broadly deltoid, short-stalked, the margins irregularly lobed, floating; the fertile leaves taller, completely divided into long whip-like segments: sporangia with a very small annulus, and containing 32 spores. Fla. to S. Amer.

Thalictroides

Brongn. Sterile leaves narrowly deltoid, long-stalked, 1-2 pinnatifid into deltoid segments not floating; fertile leaves similar but with linear segments: annulus well developed. Old World tropics.

R. C. Benedict.